Synthetic approaches towards nucleocidin and selected analogues; anti-HIV activity in 4′-fluorinated nucleoside derivatives

Nucleocidin 1 has been synthesised from the adenosine derivative 4 via the intermediacy of the dihalogeno compound 9. The latter compound showed slight but significant activity against HIV-infected cells while the isomer 10 and the monohalogeno compound 60 were inactive. Synthetic approaches towards other 4′-fluorinated nucleoside derivatives are also described. The epimeric 4′-fluorinated nucleosides 26 and 27 displayed similar activity against HIV-infected cells to that observed for the dihalogenated compound 9.